Florida International University scientists are battling prostate cancer at the cellular level. Researchers from FIU's Biomolecular Sciences Institute (BSI) believe they can eradicate prostate cancer that returns in patients who wer ...

McGill researchers have discovered, for the first time, the importance of a key epigenetic regulator in the development of the hippocampus, a part of the brain associated with learning, memory and neural ...

Using advanced DNA sequencing methods, researchers have identified a new gene that is associated with sporadic amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease. ALS is a devastating neurodegenerative ...

Rare diseases—those that affect fewer than one in 200,000 people—are often identified early in life. Some 30 percent of children afflicted by these "orphan diseases" do not live to see their fifth birthday. ...

Dirk Schübeler and his group at the Friedrich Miescher Institute for Biomedical Research (FMI) identify determinants that set epigenetic marks along the genome. The new study, published in Nature, shows ...

Researchers from the Massachusetts General Hospital (MGH) Cancer Center and Boston University School of Medicine (BUSM) have identified the first potential treatment targeting a pathway by which several aggressive ...

A common polymorphism - a variation in a person's DNA sequence that is found with regularity in the general population - can lead to a chain of events that dictates how a tumor will progress in certain types ...

A computer program that cross-references disease symptoms with DNA sequencing data can detect the faulty genes responsible for rare disorders with greater accuracy than other methods. Developed by scientists ...

Scientists from the US Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have learned new details about how an important tumor-suppressing protein, called p53, binds to the human ...

Thousands of never-before-seen genetic variants in the human genome have been uncovered using a new genome sequencing technology. These discoveries close many human genome mapping gaps that have long resisted ...

Mice and humans share a lot more than immediately meets the eye, and their commonalities include their telomeres, protective ends on chromosomes. But in recent years, the role of one particular protein at telomeres has puzzled ...

DNA sequence

A DNA sequence or genetic sequence is a succession of letters representing the primary structure of a real or hypothetical DNA molecule or strand, with the capacity to carry information as described by the central dogma of molecular biology.

The possible letters are A, C, G, and T, representing the four nucleotide bases of a DNA strand — adenine, cytosine, guanine, thymine — covalently linked to a phosphodiester backbone. In the typical case, the sequences are printed abutting one another without gaps, as in the sequence AAAGTCTGAC, read left to right in the 5' to 3' direction. Short sequences of nucleotides are referred to as oligonucleotides and are used in a range of laboratory applications in molecular biology. With regard to biological function, a DNA sequence may be considered sense or antisense, and either coding or noncoding. DNA sequences can also contain "junk DNA."

Sequences can be derived from the biological raw material through a process called DNA sequencing.

In some special cases, letters besides A, T, C, and G are present in a sequence. These letters represent ambiguity. Of all the molecules sampled, there is more than one kind of nucleotide at that position. The rules of the International Union of Pure and Applied Chemistry (IUPAC) are as follows: